Automotive muffler

Abstract

In a muffler comprising a shell formed by joining a pair of shell halves each including a bottom wall and a side wall and defining an opening opposite to the bottom wall, the shell halves being joined to each other at the openings thereof, the muffler further comprising an inlet pipe for introducing exhaust gas into the shell and an outlet pipe for expelling exhaust gas from inside the shell, a depth of one of the shell halves is greater than a depth of the other shell half, and the inlet pipe and the outlet pipe are connected to the side wall of the one shell half so that the overall plane stiffness of the shell is well balanced and maximized. Therefore, without adding any reinforcement or increasing the wall thickness of the shell, the acoustic emission from the muffler can be minimized.

Description

TECHNICAL FIELD[0001]The present invention relates to a muffler forming a part of an exhaust system of an internal combustion engine of a motor vehicle.PRIOR ART[0002]A motor vehicle powered by an internal combustion engine is provided with an exhaust system which includes an exhaust manifold, a catalyst device, an exhaust pipe and a muffler for the purposes of removing noxious substances from the exhaust gas and reducing exhaust noises. The muffler typically consists of a shell made of steel plate, a plurality of separators that separate the interior of the shell into a number compartments (such as an expansion chamber and a resonance chamber), an inlet pipe for introducing exhaust gas into the shell and an outlet pipe extending rearward from the shell to expel the exhaust gas. These components are usually joined together by welding such as laser welding. See JP2004-245052A, for instance. The expansion chamber attenuates the pulsating pressure changes of the exhaust gas, and the re...

AI Technical Summary

Benefits of technology

[0009]A second object of the present invention is to provide an automotive muffler which is formed by a shallow shell, but is effective in minimizing exhaust noises owing to an increased plane stiffness of the shell wall.

[0028]These side edges increase the stiffness of the separator. When each side flange is detached from an opposing wall of the corresponding shell half, the upper and lower flanges are given with a freedom in deforming in conformity with the opposing wall of the shell so that the separator can be installed in the shell in a mechanically stable manner without causing any undue stress in the welded part thereof.

Problems solved by technology

However, in modern motor vehicles, the floor panel is generally planar in shape, and allows a relatively limited space thereunder.

Low profile mufflers are advantageous for use in modern vehicle body designs, but have the disadvantage of lacking in plane stiffness.

A lack in plane stiffness means an increase in an undesired acoustic emission from the muffler owing to the vibrations of the shell wall of the muffler.

According to this prior art, each shell half is provided with a relatively large depth so that the side wall may not have an adequate stiffness, and may cause an undesired acoustic emission therefrom.

However, when the shell is formed by a pair of shallow upper and lower shell halves, separator plates may not be press fitted into the shell, and certain welding or bonding arrangements are required to fixedly place the separator plates within the shell.

As the separator plates are required to be connected to the inner side of the shell wall in an air tight manner, there is a considerable difficulty in holding the edges of the separator plates in close contact with the inner side of the shell wall while the separator plates are welded to the shell wall.

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